Artificial Light May Be Linked to Breast Cancer

Intensified exposure to artificial light at night might be another cause of breast cancer in women, according to the researcher Itai Kloog of the University's Deptartment of Natural Resources and Environmental Management. "We found that the stronger the lighting, the higher the incidence of cancer," he said. "The more lit up a settlement was at night, the higher were the rates of breast cancer."

Kloog investigated the level of lighting in 214 Israeli settlements. In addition, he surveyed 100 women who suffered from breast cancer and 100 healthy women. "There was a significant difference between the group of cancer patients and the healthy group in their proximity to large shopping centres, malls, and entertainment areas," the researcher reports. These places, he explained, generally make use of "blue" lighting, which is much stronger than ordinary bulbs. They also have much more extensive lighting systems.

Another difference between the two groups of women had to do with bedroom lights at night. "The body produces the hormone melatonin at night, when it is dark," Kloog explained. "This hormone delays the growth of cancerous cells. Therefore, any reduction of this hormone in the blood as a result of exposure to artificial lighting constitutes another factor putting women at risk of falling ill with breast cancer."

Kloog doesn't suggest we walk around only with candles at night. He does, though, warn against artificial light trickling into the bedroom all night from outside. He advises shutting unnecessary house lights at night and to be careful not to fall asleep in front of a television that is left on. Deserted areas of the city, like an industrial area, should be blacked out at night, he feels. "All this reduction will not only prevent unnecessary exposure to artificial light," Kloog remarks. "It will also reduce pollution from less use of electricity and from less electricity production. And it will save cities thousands of shekels in reduced electric use."